Method for transferring container

ABSTRACT

A method for transferring a container configured to hold at least one article used in semiconductor fabrication is provided. The method includes moving a transferring mechanism to a first position that is adjacent to the original space; producing an image of an edge of the container that is adjacent to the original space using an optical receiver before the container is moved to a destination space; and performing an image analysis of the image to determine whether to move the container to the destination space.

PRIORITY CLAIM AND CROSS-REFERENCE

This application is a Continuation Application of U.S. patentapplication Ser. No. 15/873,061, filed on Jan. 17, 2018, now U.S. Pat.No. 10,821,871, which claims priority of U.S. Provisional ApplicationNo. 62/583,054, filed on Nov. 8, 2017, the entirety of which areincorporated by reference herein.

BACKGROUND

In the process of manufacturing a semiconductor device, transporting orconveying articles for processing is a task that is performed throughoutthe manufacturing process. Conventionally, articles are conveyed in afabrication plant by automatically guided vehicles or overhead transportvehicles that travel on predetermined routes or tracks. For theconveyance of articles, the articles are normally loaded intocontainers, such as SMIF (a standard machine interface) or FOUP (a frontopening unified pod), and then picked up and placed in the automaticconveying vehicles.

A semiconductor wafer is one sort of article that may be positioned inthe container, and various device elements are formed on thesemiconductor wafer. Examples of device elements that are formed on thesemiconductor wafer include transistors (e.g., metal oxide semiconductorfield effect transistors (MOSFET), complementary metal oxidesemiconductor (CMOS) transistors, bipolar junction transistors (BJT),high-voltage transistors, high-frequency transistors, p-channel and/orn-channel field-effect transistors (PFETs/NFETs), etc.), diodes, andother applicable elements.

Alternatively, articles positioned in the containers may include a testwafer. The test wafer is used to monitor the integrity of a work stationto be used in a semiconductor device fabrication process flow.Alternatively, articles positioned in the containers may include aphotomask or reticle. The photomask or the reticle is used in aphotolithography operation of the semiconductor device fabricationprocess flow.

Although existing methods for transferring the container have generallybeen adequate for their intended purposes, they have not been entirelysatisfactory in all respects. Consequently, it would be desirable toprovide a solution for the process control for container-transferoperations.

BRIEF DESCRIPTION OF THE DRAWINGS

Aspects of the present disclosure are best understood from the followingdetailed description when read with the accompanying figures. It shouldbe noted that, in accordance with the standard practice in the industry,various features are not drawn to scale. In fact, the dimensions of thevarious features may be arbitrarily increased or reduced for clarity ofdiscussion.

FIG. 1 is a schematic view of an automatic material handling system(AMHS), in accordance with some embodiments.

FIG. 2 is a schematic view of a stocker, in accordance with someembodiments.

FIG. 3 is a schematic view of a transferring mechanism and a storageshelve, in accordance with some embodiments.

FIG. 4 is a block diagram of a monitoring module and a control module,in accordance with some embodiments.

FIG. 5 is a flow chart illustrating a method for transferring acontainer, in accordance with some embodiments.

FIG. 6 is a schematic view of one stage of a method for transferring acontainer, in accordance with some embodiments.

FIG. 7A is an example of a first image recorded by an optical receiverin a normal condition, in accordance with some embodiments.

FIG. 7B is an example of a first image recorded by an optical receiverin an abnormal condition, in accordance with some embodiments.

FIG. 8 is a schematic view of one stage of a method for transferring acontainer, in accordance with some embodiments.

FIG. 9 is a schematic view of one stage of a method for transferring acontainer, in accordance with some embodiments.

FIG. 10A is an example of a second image recorded by an optical receiverin a normal condition, in accordance with some embodiments.

FIG. 10B is an example of a second image recorded by an optical receiverin an abnormal condition, in accordance with some embodiments.

FIG. 11 is a schematic view of one stage of a method for transferring acontainer, in accordance with some embodiments.

FIG. 12A is an example of a third image recorded by an optical receiverin a normal condition, in accordance with some embodiments.

FIG. 12B is an example of a third image recorded by an optical receiverin an abnormal condition, in accordance with some embodiments.

FIG. 12C is an example of a third image recorded by an optical receiverin an abnormal condition, in accordance with some embodiments.

DETAILED DESCRIPTION

The following disclosure provides many different embodiments, orexamples, for implementing different features of the subject matterprovided. Specific examples of solutions and arrangements are describedbelow to simplify the present disclosure. These are, of course, merelyexamples and are not intended to be limiting. For example, the formationof a first feature over or on a second feature in the description thatfollows may include embodiments in which the first and second featuresare formed in direct contact, and may also include embodiments in whichadditional features may be formed between the first and second features,such that the first and second features may not be in direct contact. Inaddition, the present disclosure may repeat reference numerals and/orletters in the various examples. This repetition is for the purpose ofsimplicity and clarity and does not in itself dictate a relationshipbetween the various embodiments and/or configurations discussed.

Furthermore, spatially relative terms, such as “beneath,” “below,”“lower,” “above,” “upper” and the like, may be used herein for ease ofdescription to describe one element or feature's relationship to anotherelement(s) or feature(s) as illustrated in the figures. The spatiallyrelative terms are intended to encompass different orientations of thedevice in use or operation in addition to the orientation depicted inthe figures. The apparatus may be otherwise oriented (rotated 90 degreesor at other orientations) and the spatially relative descriptors usedherein may likewise be interpreted accordingly. It is understood thatadditional operations can be provided before, during, and after themethod, and some of the operations described can be replaced oreliminated for other embodiments of the method.

FIG. 1 illustrates a schematic view of an automatic material handlingsystem (AMHS) 1, in accordance with some embodiments. In someembodiments, the automatic material handling system 1 includes aninter-bay transportation apparatus 22, a number of processing bays 24,and a number of stockers 30.

The inter-bay transportation apparatus 22 is configured to convey thecontainers among the stockers 30. In some embodiments, the inter-baytransportation apparatus 22 is an automated transportation vehicles(AGV) system, a rail guided vehicles (RGV) system, or an overhead hoisttransport (OHT) system. For simplicity, only a guided route, a guidedrail or an overhead track of the inter-bay transportation apparatus 22is illustrated in FIG. 1.

Each processing bay 24 is configured to perform a respective type ofprocessing operation in the process flow, such as photolithography,etching, diffusion, ion implantation, deposition or passivation, in asemiconductor device fabrication process flow. In some embodiments, eachprocessing bay 24 includes a number of processing tool 26 and anintrabay transportation apparatus 28.

In some embodiments, the processing tool 26 include a chemicalmechanical polishing (CMP) apparatus, a physical vapor deposition (PVD)apparatus, a chemical vapor deposition (CVD) apparatus, an ion implantapparatus, an epitaxy apparatus, a sputter apparatus, a thermalprocessing apparatus, an etching apparatus, a photolithographyapparatus, or another suitable apparatus. In some embodiments, thesemiconductor manufacturing process includes a CMP process, a PVDprocess, a CVD process, an ALD process, a doping process, a screenprinting process, a dry etching process, a wet etching process, aphotolithography process, or another suitable process.

The intrabay transportation apparatus 28 is configured to convey theworkpiece between the processing tool 26 within the processing bay 24.In some embodiments, the intrabay transportation system 28 is an AGVsystem, an RGV system, or an OHT system. For simplicity, only a guidedroute, a guided rail or an overhead track of the intrabay transportationapparatus 28 is illustrated in FIG. 1.

The stockers 30 are utilized for providing input/out to processing bays24, or to processing tool 26 located on the processing bays 24. Theinter-bay transportation apparatus 22 is used to perform lottransportation between processing bays 24. In this configuration, thestockers 30 of the automatic material handling system become the pathwayfor both input and output of the bays 24.

In AMHS 1, the stockers 30 are widely used in conjunction withautomatically guided or overhead transport vehicles, either on theground or suspended on tracks, for the storing and transporting ofarticles in containers, such as SMIF (standard machine interface) orFOUP (front opening unified pod). Three possible configurations forutilizing a stocker may be provided.

In the first configuration, a stocker is utilized for storing articlesin SMIF pods and transporting them first to a first tool, then to asecond tool, and finally to a third tool for three separate processingsteps to be conducted on the articles. After the processing in the thirdtool is completed, the SMIF pod is returned to the stocker for possibleconveying to another stocker.

In the second configuration, a stocker and a plurality of bufferstations are used to accommodate different processes to be conducted inthe first tool, the second tool and the third tool. The container mayfirst be delivered to a first buffer station from the stocker and maywait there for processing by the first tool. Second and third bufferstations are similarly utilized in connection with the second and thirdtools. In the third configuration, a stocker is provided for controllingthe storage and conveying of articles to the first, second and thirdtools. After a container is delivered to one of the three tools, thecontainer is always returned to the stocker before it is sent to thenext processing tool.

FIG. 2 is a schematic view of the stocker 30, in accordance with someembodiments. The stocker 30 is configured to automation storage andretrieval. In some embodiments, the stocker 30 includes a main body 32,a load port 34, a number of storage shelves 36 a, 36 b, 36 c and 36 dand a transferring mechanism 38.

In some embodiments, the main body 32 is a rectangular enclosure andincludes a longitudinal side wall 321 and two transverse side walls 323and 324. The two transverse side walls 323 and 324 are connected to twoedges of the longitudinal side wall 321. One or more openable/closeableand sealable access doors 322 are positioned on the transverse sidewalls 323.

The load port 34 is configured to support and dock the containers 10 forfacilitating insertion and removal of containers 10 into/from the mainbody 32 of the stocker 30. The load port 34 is positioned along a railof the inter-bay transportation apparatus 22 or a rail of the intrabaytransportation apparatus 28 (FIG. 1) so as to receive the containers 10transferred from the vehicle of the inter-bay transportation apparatus22 or the intra bay transportation apparatus 28. The load ports 34 arepositioned in such a way that they correspond to the access door 322 ofthe main body 32 for transferring containers 10 into the main body 32.

In some embodiments, as shown in FIG. 2, the load port 34 has a couplinginterface 341 that includes a number of protruding coupling pins 342corresponding to the coupling mechanisms such as the grooves (not shownin figures) of each container 10 so as to successfully couple to thecontainer 10 and dock the container 10 at a predetermined position onthe load port 34. The dimensions of the coupling pins 342 correspond tothe dimensions of the coupling mechanisms of the container 10.

The storage shelves 36 a, 36 b, 36 c and 36 d are configured tofacilitate the storing of the containers 10 within the main body 32. Insome embodiments, the storage shelves 36 a, 36 b, 36 c and 36 d arepositioned on the main body 32, such as on the longitudinal side wall321 and the other longitudinal side wall. In some embodiments, as shownin FIG. 3, the storage shelf 36 a includes a plate 361, a number ofcoupling pins 362 and a number of embossments 364. The plate 361 has aU-shape and is used to support the container 10 when the container 10 ispositioned on the storage shelf 36 a. However, it should be noted thatthe configuration of the plate should not be limited to that shown inFIG. 4.

The coupling pins 362 are positioned on an upper surface of the plate361. The coupling pins 362 correspond to the coupling mechanisms such asthe grooves (not shown in figures) of each container 10 so as tosuccessfully couple to the container 10 and dock the container 10 at apredetermined position on the storage shelf 36 a. The dimensions of thecoupling pins 362 correspond to the dimensions of the couplingmechanisms of the container 10. Two embossments 364 are formed on theupper surface of the plate 361. The two embossments 364 are immediatelyconnected to the front edge 3610 of the plate 361, in accordance withsome embodiments. The two embossments 364 are used for positioning therobotic arm 383 (which will described later) of the transferringmechanism 38.

Referring back to FIG. 2, the transferring mechanism 38 is configured tomove the container 10 within the stocker 30. In some embodiments, thetransferring mechanism 38 includes a rail 381 and a crane 382, and arobotic arm 383. The crane 382 and the rail 381 are configured to movethe robotic arm 383 along the length of the longitudinal side wall 321.The crane 382 is also configured to move the robotic arm 383 along theheight of the longitudinal side wall 321. The length and height of thelongitudinal side wall 321 are respectively parallel to andperpendicular to the floor of a FAB. The robotic arm 383 is configuredto move the container 10 along a plane that is perpendicular to thelongitudinal side wall 321.

A number of elements which are going to be moved by the transferringmechanism 38 during the movement of the container 10 are located on therobotic arm 383. For example, the transferring mechanism 38 furtherincludes a blade 384, a guard plate 386 and a supporting assembly 39.The blade 384, the guard plate 386 and the supporting assembly 39 arepositioned on the robotic arm 383. According to some embodiments, theconfiguration of the blade 384, the guard plate 386 and the supportingassembly 39 are described below.

The blade 384 is configured for directly supporting the container 10while the container transfer. In some embodiments, as shown in FIG. 3, anumber of coupling pins 385 are positioned on an upper surface of theblade 384. The coupling pins 385 correspond to the coupling mechanismssuch as the grooves (not shown in figures) of each container 10 so as tosuccessfully couple to the container 10 and dock the container 10 at apredetermined position on the blade 384. The dimensions of the couplingpins 385 correspond to the dimensions of the coupling mechanisms of thecontainer 10.

The guard plate 386 is connected to a rear side (a side that is oppositeto a front side which directly faces the storage shelf 36 a) of theblade 384. The guard plate 386 is perpendicular to the blade 384 and isconfigured to protect the container 10 from being dropped while it isbeing conveyed. The configurations of the storage shelves 36 b, 36 c and36 d are similar to the configurations of the storage shelf 36 a andwill not be repeated, for brevity.

The supporting assembly 39 is configured to support an optical receiver41 (which will be described later). In some embodiments, the supportingassembly 39 includes a stand 391, a lower mounting member 392, and anupper mounting member 393. The stand 391 is vertically positioned on therobotic arm 383 and is located adjacent to the blade 384. The height ofthe stand 391 may be greater than the height of the guard plate 386.

The lower mounting member 392 is fixed on an upper end of the stand 391.The upper mounting member 393 is detachably connected to the lowermounting member 392. In some embodiments, the upper mounting member 393is connected to the lower mounting member 392 via fastening members,such as screws. The upper mounting member 393 may include two brackets394 and 395 connected to one another by a hinge, and the angle betweenthe two brackets 394 and 395 can be adjusted automatically or manually.

Referring to FIG. 4 with reference to FIG. 3, the monitoring module 40includes an optical receiver 41 and an image processor 42, in accordancewith some embodiments. As shown in FIG. 3, the optical receiver 41 ispositioned at the supporting assembly 39 such that the optical receiver41 is moved to a particular position in the main body 32 (FIG. 2). Insome embodiments, the optical receiver 41 includes a charge-coupleddevice (CCD).

Specifically, the optical receiver 41 is mounted on the upper mountingmember 393 of the supporting assembly 39. The position and theorientation angle of the optical receiver 41 can be adjusted by changingthe position of the upper mounting member 393 on the lower mountingmember 392 or by changing the angle between the two brackets 394 and395. The optical receiver 41 is used to investigate particular objectsor locations in the stocker 30.

Referring FIG. 4 again, the image processor 42 is connected to theoptical receiver 41 to receive the electronic signal from the opticalreceiver 41. Then the image processor 42 analyzes the image to producean image analysis result regarding the image investigated by the opticalreceiver 41.

The FDC module 50 is configured to detect faults within the stocker 30.The FDC module 50 monitors parameters associated with the stocker 30 andevaluates the parameters to detect abnormalities, or faults, duringoperation of the stocker 30. In some embodiments, the FDC module 50receives an image analysis result from the image processor 42 anddetermines if abnormalities or faults occur during the transportation ofthe container 10 in the stocker 30.

The FDC module 50 may be a computer system. In one example, the computersystem includes a network communications device or a network computingdevice (for example, a mobile cellular phone, a laptop, a personalcomputer, a network server, etc.) capable of communicating with anetwork. In accordance with embodiments of the present disclosure, thecomputer system performs specific operations via a processor executingone or more sequences of one or more instructions contained in a systemmemory component. In one example, such instructions are read into asystem memory component from another computer readable medium, such as astatic storage component or a disk drive component. In another example,hard-wired circuitry is used in place of (or in combination with)software instructions to implement the present disclosure.

FIG. 5 is a flow chart illustrating a method 60 for transferring thecontainer 10 in the stocker 30, in accordance with some embodiments. Forillustration, the flow chart will be described in company with theschematic views shown in FIGS. 1-4 and 6-12C. Some of the stagesdescribed can be replaced or eliminated for different embodiments.

The following discussion will use the transfer of the container 10 fromthe load port 34 to one of the storage shelves 36 a as an example. Theload port 34 is referred to as the original space, and the storage shelf36 a where the container is going to be deposited is referred to as thedestination space for the purpose of illustration.

The method 60 includes operation S1, in which the transferring mechanism38 is moved to a first position that is adjacent to an original space onwhich the container 10 is placed. In some embodiments, in order totransfer the container 10 which is placed on the original space, thetransferring mechanism 38 is moved to a first position, as shown in FIG.6, so as to allow the robotic arm 383 to directly face the access door322 of the stocker 30. When the transferring mechanism 38 is moved tothe first position, the optical receiver 41 is able to produce an imageof the bottom edge of the container 10 that is adjacent to the originalspace.

In some embodiments, before the movement of the transferring mechanism38 in operation S1, the optical receiver 41 is mounted on thetransferring mechanism 38, and the orientation angle of the opticalreceiver 41 is adjusted so as to allow the targeted subject to be imagedwhen the transferring mechanism 38 is moved to a first position. In someembodiments, the orientation angle of the optical receiver 41 isadjusted manually and maintained at a predetermined angle during themovement of the transferring mechanism 38. In some embodiments, theorientation angle of the optical receiver 41 is dynamically adjusted byan electrical actuator according to the position of the transferringmechanism 38.

In some embodiments, before the movement of the transferring mechanism38 in operation S1 or during the movement of the transferring mechanism38 in operation S1 the container is placed on the original space by avehicle of the inter-bay transportation apparatus 22 or a vehicle of theintra bay transportation apparatus 28 (FIG. 1).

The method 60 also includes operation S2, in which an inspection processis performed. In the inspection process, a first image of the originalspace or the container 10 is produced. In some embodiments, once thetransferring mechanism 38 is moved to the first position as shown inFIG. 6, the optical receiver 41 is operated to produce a first image ofthe original space and/or the container 10. In some embodiments, asshown in FIG. 7A, at least a bottom edge 11 of the container 10 and anupper portion of the original space that is in contact with thecontainer 10 are imaged. The first image of the original space or thecontainer 10 is then transmitted to the image processor 42 for imageanalysis.

The method 60 also includes operation S3, in which the result of animage analysis of the first image is generated so as to determine if anabnormality occurs. In some embodiments, the image processor 42 performsan image analysis of the first image. The image analysis includesreading the real-time video image captured by the optical receiver 41.The image analysis further includes recognizing the bottom edge 11 ofthe container 10. In addition, the image analysis includes constructinga movable reference line M1 that is overlapped or parallel to the bottomedge 11 of the container 10.

Moreover, the image analysis includes comparing the first image with afirst template image by employing a predetermined algorithm, such asmatrix multiplication. As shown in FIG. 7A, the first template imageshows a horizontal reference line H1. The horizontal reference line H1indicates a line that represents the correct position of the bottom edge11 of the container 10 if the container 10 is centered relative to theoriginal space. The horizontal reference line H1 may extend in ahorizontal direction that is parallel to a floor of a FAB where thestocker 30 is located. The data associated with the first template imagemay be recorded in a database and sent to the image processor 42 beforethe image analysis is performed on the first image. The image processor42 determines if the movable reference line M1 is parallel to oroverlaps the horizontal line H1 and passes the result to the FDC module50.

FIG. 7A shows an example of a first image captured by the opticalreceiver 41 in a normal condition. In cases where the container 10 isproperly located on the original space, the bottom edge 11 of thecontainer 10 is parallel to the upper surface of the original space. Asa result, the image analysis of the first image shown in FIG. 7Arepresents that the movable reference line M1 of the first image isparallel to or overlaps with the horizontal reference line H1 of thetemplate image. The image processor 42 sends data indicative of theoutcome of the image analysis to the FDC module 50, and the FDC module50 determines that the result of the image analysis is acceptable andthe method continues to operation S4.

In operation S4, the container 10 is removed from the original space andmoved to a second position that is adjacent to the destination space.Specifically, when the result of the image analysis is acceptable, theFDC module 50 issues a signal to the transferring mechanism 38 to drivethe robotic arm 383 of the transferring mechanism 38 to move the blade384 toward the container 10 in the direction indicated by the arrowshown in FIG. 6 so as to place the container 10 on the blade 384.

Afterwards, the transferring mechanism 38 removes the container 10 fromthe first position which is adjacent to the original space and movestoward a second position that is adjacent to the designation space alongthe directions indicated by the arrows shown in FIG. 8. During themovement of the transferring mechanism 38, the crane 382 and the rail381 are configured to move the robotic arm 383 along the length of thelongitudinal side wall 321. In addition, the crane 382 is configured tomove the robotic arm 383 along the height of the longitudinal side wall321. Therefore, the blade 384 and the container 10 are moved to thesecond position as shown in FIG. 9. When the transferring mechanism 38is moved to the second position, the optical receiver 41 is able toproduce an image of the designation space.

FIG. 7B shows an example of a first image captured by the opticalreceiver 41 in an abnormal condition. In cases where the container 10 isobliquely positioned on the original space due to the bottom of thecontainer 10 abutting the coupling pin 342, the bottom edge 11 of thecontainer 10 is not parallel to the upper surface of the original space.As a result, the image analysis of the first image shown in FIG. 7Brepresents that the movable reference line M1 of the first image is notparallel to and doesn't overlap with the horizontal reference line H1 ofthe template image. The image processor 42 sends data indicative of theoutcome of the image analysis to the FDC module 50, and the FDC module50 determines that the result of the image analysis is not acceptableand the method continues to operation S10.

In operation S10, the FDC module 50 will take immediate action andinform maintenance personnel to properly handle it. As a result, damageto the container 10 or the transferring mechanism 38 for transferringthe container 10 caused by the container transfer being performed underirregular conditions can be mitigated or avoided, and wafer scrap can bereduced.

The method 60 also includes operation S5, in which another inspectionprocess is performed. In the inspection process of operation S5, asecond image of the destination space is produced. In some embodiments,once the transferring mechanism 38 has moved the container 10 to thesecond position as shown in FIG. 9, the optical receiver 41 is operatedto produce a second image of the destination space. In some embodiments,as shown in FIG. 10A, at least the front edge 3610 of the plate 361 andthe embossments 364 are imaged by the optical receiver 41. The secondimage of the destination space is then transmitted to the imageprocessor 42 for image analysis.

The method 60 also includes operation S6, in which the result of animage analysis of the second image is generated so as to determine if anabnormality occurs. In some embodiments, the image processor 42 performsan image analysis of the second image. The image analysis includesreading the real-time video image captured by the optical receiver 41.The image analysis further includes recognizing at least two referencepoints of the destination space. In addition, the image analysisincludes constructing a stationary reference line S1 that connects thetwo reference points.

In the embodiments shown in FIG. 10A, the two embossments 364 areselected as the two reference points for image analysis. However, itshould be appreciated that other elements of the destination space canbe selected as the reference points. For examples, the coupling pins 362(FIG. 3) can be selected as the two reference points for image analysis.

Moreover, the image analysis includes comparing the second image with asecond template image by employing a predetermined algorithm, such asmatrix multiplication. As shown in FIG. 10A, the second template imageshows a horizontal reference line H2. The horizontal reference line H2indicates a line that represents the correct position of the referencepoints if the destination space is preserved as a desired condition. Thehorizontal reference line H2 may be extended in a horizontal direction.The data associated with the second template image may be recorded in adatabase and passed to the image processor 42 before the image analysisis performed on the second image. The image processor 42 determines ifthe stationary reference line S1 is parallel to or overlaps thehorizontal line H2. Afterwards, the image processor 42 passes the resultof the image analysis of the second image to the FDC module 50.

FIG. 10A shows an example of a second image captured by the opticalreceiver 41 in a normal condition. In cases where the destination spaceis preserved as a desired condition, the two embossments 364 are locatedat the same horizontal level. As a result, the image analysis of thesecond image shown in FIG. 10A represents that the stationary referenceline S1 of the second image is parallel to or overlaps with thehorizontal reference line H2 of the template image. The image processor42 passes data indicative of the outcome of the image analysis of thesecond image to the FDC module 50, and the FDC module 50 determines thatthe result of the image analysis is acceptable and the method continuesto operation S7.

In operation S7, the container 10 is placed on the destination space. Insome embodiments, when the result of the image analysis is acceptable,the FDC module 50 issues a signal to the transferring mechanism 38 todrive the robotic arm 383 of the transferring mechanism 38 to movetoward the destination space in the direction indicated by the arrowshown in FIG. 9 so as to place the container 10 on the plate 361.Afterwards, the robotic arm 383 is retrieved back to the second positionalong an opposite direction as indicated by the arrow shown in FIG. 11.

FIG. 10B show an example of a second image captured by the opticalreceiver 41 in an abnormal condition. In cases where the destinationspace is not preserved as a desired condition due to collision or otherfactors, it may be that the two embossments 364 are not located at thesame horizontal level. As a result, the image analysis of the secondimage shown in FIG. 10B represents that the stationary reference line S1of the second image is not parallel to and doesn't overlap with thehorizontal reference line H2 of the template image. The image processor42 passes data indicative of the outcome of the image analysis of thesecond image to the FDC module 50, and the FDC module 50 determines thatthe result of the image analysis is not acceptable and the methodcontinues to operation S10.

In operation S10, the FDC module 50 will take immediate action andinform maintenance personnel to properly handle it. As a result, damageto the container 10, the transferring mechanism 38, or the destinationspace caused by the container transfer being performed under irregularconditions can be mitigated or avoided, and wafer scrap can be reduced.

The method 60 also includes operation S8, in which yet anotherinspection process is performed. In the inspection process of operationS8, a third image of the destination space and/or the container 10 isproduced after the container 10 is deposited to the destination space.In some embodiments, once the transferring mechanism 38 is moved back tothe second position as shown in FIG. 11, the optical receiver 41 isoperated to produce the third image of the destination space or thecontainer 10. In some embodiments, as shown in FIG. 12A, the front edge3610 of the plate 361 and the embossments 364 are imaged by the opticalreceiver 41. Additionally, the bottom edge 11 of the container 10 isimaged by the optical receiver 41. The third image of the destinationspace and/or the container 10 is then transmitted to the image processor42 for image analysis.

The method 60 also includes operation S9, in which the result of animage analysis of the third image is generated so as to determine if anabnormality occurs. In some embodiments, the image processor 42 performsan image analysis of the third image. The image analysis includesreading the real-time video image captured by the optical receiver 41.The image analysis further includes recognizing the bottom edge 11 ofthe container 10 and the two embossments 364 of the destination space.In addition, the image analysis includes constructing a stationaryreference line S2 that connects the two embossments 364, and a movablereference line M2 that is overlapped or parallel to the bottom edge 11of the container 10 as well. Moreover, the image analysis includesdetermining whether the stationary reference line S2 and the movablereference line M2 are parallel to one another. Afterwards, the result ofthe image analysis of the third image is sent to the FDC module 50.

FIG. 12A shows an example of a third image captured by the opticalreceiver 41 in a normal condition. In cases where the container 10 isproperly located on the destination space, the bottom edge 11 of thecontainer 10 is parallel to the plate 361 of the destination space. As aresult, the image analysis of the third image shown in FIG. 12Arepresents that the movable reference line M2 is parallel to thestationary reference line S2. The image processor 42 passes dataindicative of the outcome of the image analysis of the third image tothe FDC module 50, and the FDC module 50 determines that the result ofthe image analysis is acceptable.

When the result of the image analysis is acceptable, the transportationof the container 10 from the original space to the destination space isfinished. Afterwards, the FDC module 50 issues a signal to thetransferring mechanism 38 to move robotic arm 383 to the other positionin the stocker 30 to transfer the other container 10.

FIG. 12B shows an example of a third image captured by the opticalreceiver 41 in an abnormal condition. In cases where an element of thedestination space, such as the plate 361, is damaged or deformed due tocollision during the movement of the blade 384 (FIG. 3) in operation S7,the image analysis of the third image may represent that the movablereference line M2 is parallel to the stationary reference line S2 eventhough both the container 10 and the destination space are oblique.

In order to detect this abnormal condition shown in FIG. 12B, the imageanalysis further includes calculating an angle of the stationaryreference line S2 and/or the movable reference line M2 relative to ahorizontal reference line H3 of a third template image by employing apredetermined algorithm, such as matrix multiplication. The horizontalreference line H3 indicates a line that represents the correct positionof the reference points if the destination space is preserved as adesired condition. The horizontal reference line H3 may be extended in ahorizontal direction. The data associated with the third template imagemay be recorded in a database and passed to the image processor 42before the image analysis is performed on the third image.

The image processor 42 calculates the angle θ formed between thestationary reference line S2 and the horizontal reference line H3 or theangle θ formed between the movable reference line M2 and the horizontalreference line H3. Afterwards, the image processor 42 sends dataindicative of the outcome of the image analysis of the third image tothe FDC module 50. If the calculated angle is smaller than the presentvalue, the FDC module 50 determines that the result of the imageanalysis is acceptable; otherwise, the FDC module 50 determines that theresult of the image analysis is not acceptable. In some embodiments, theangle θ formed between the stationary reference line S2 and thehorizontal reference line H3 or the angle θ formed between the movablereference line M2 and the horizontal reference line H3 is in a rangefrom about 1 degree to about 2 degrees. In some other embodiments, theangle θ is less than about 2 degrees.

FIG. 12C shows an example of a third image captured by the opticalreceiver 41 in an abnormal condition. In cases where the container 10 isobliquely positioned on the destination space due to the bottom of thecontainer 10 abutting the coupling pin 362, the bottom edge 11 of thecontainer 10 is not parallel to plate 361 of the destination space. As aresult, the image analysis of the first image shown in FIG. 12Brepresents that the movable reference line M2 is not parallel to thestationary reference line S2. The image processor 42 passes dataindicative of the outcome of the image analysis to the FDC module 50,and the FDC module 50 determines that the result of the image analysisis not acceptable and the method continues to operation S10.

In operation S10, the FDC module 50 will take immediate action andinform maintenance personnel to properly handle it. As a result, damageto the container 10 due to improper placement of the container 10 on thedestination space can be mitigated or avoided, and wafer scrap can bereduced.

While the above discussion uses a transfer of the container 10 from theload port 34 to the storage shelf 36 a as an example, it is contemplatedthat the method 60 can be implemented by the stocker 30 to move thecontainer 10 from any original space within the stocker 30 to anydestination space within the stocker 30. In cases where the container 10is moved from the storage shelf 36 a to the load port 34, the storageshelf 36 a is referred to as the original space, and the load port 34 isreferred to as the destination space. In some other embodiments, thecontainer 10 is moved from the storage shelf 36 a to a purge station(not shown in figures) located in the main body 32 so as to purgenitrogen or another purging gas into the container 10. In this case, thestorage shelf 36 a is referred to as the original space, and the purgestation is referred to as the destination space.

In some illustrated embodiments, the transferring mechanism 38 patrolsthe main body 32 of the stocker 30 with no container 10 loaded thereonand stays in front of each of the storage shelves 36 a, 36 b, 36 c and36 d for a few seconds to image each of the storage shelves 36 a, 36 b,36 c and 36 d. Afterwards, the images captured by the optical receiver41 are transmitted to the image processor 42 for image analysis so as tocheck the health of storage shelves 36 a, 36 b, 36 c and 36 d, andinform maintenance personnel to perform maintenance if any of thestorage shelves 36 a, 36 b, 36 c and 36 d is not preserved in thedesired condition.

Embodiments of method for transferring containers in the stocker performan inspection process to determine if an abnormality occurs. Theinspection process is performed before a withdrawal of the containerfrom an original space to make sure that the container is properlyplaced on the original space. In addition, the inspection process isperformed before a deposit of the container to a destination space toconfirm that the destination space is in a proper condition forreceiving the container. Moreover, the inspection process is performedafter the deposit of the container to the destination space to ensurethat the container is perfectly placed on the destination space. Sincethe health of the hardware in the stocker for receiving the containercan be monitored in real time, maintenance can be executed immediatelywhen a fault occurs. Additionally, because the transferring process ofthe container is halted when an abnormality is detected, concerns aboutthe container falling can be eased, and damage to the article held inthe container can be prevented or mitigated.

In accordance with some embodiments, a method for transferring acontainer configured to hold at least one article used in semiconductorfabrication, comprising: moving a transferring mechanism to a firstposition that is adjacent to the original space; producing an image ofan edge of the container that is adjacent to the original space using anoptical receiver before the container is moved to a destination space;and performing an image analysis of the image to determine whether tomove the container to the destination space.

In accordance with some embodiments, a method for transferring acontainer configured to hold at least one article used in semiconductorfabrication, comprising: producing an first image of an edge of thecontainer at a first position that is adjacent to an original spaceusing an optical receiver; moving the container from the first positionto a second position that is adjacent to a destination space using atransferring mechanism when the result of an image analysis of the firstimage is accepted; producing an second image of the destination spaceusing the optical receiver; and performing an image analysis of thesecond image to determine whether to place the container at thedestination space.

In accordance with some embodiments, a stocker for storing containers,comprising: a transferring mechanism, configured to move at least onecontainer from a first position that is adjacent to an original space toa second position that is adjacent to a destination space, wherein thecontainer is configured to hold at least one article used insemiconductor fabrication and the transferring mechanism comprises: arobotic arm; and a blade, positioned on the robotic arm, and configuredto place the container at the destination space; an optical receiver,positioned at the transferring mechanism, and configured to produce animage of an edge of the container that is placed at the destinationspace; an image processor, connected to the optical receiver, andconfigured to perform an image analysis of the image to determine if anabnormality occurs.

Although the embodiments and their advantages have been described indetail, it should be understood that various changes, substitutions, andalterations can be made herein without departing from the spirit andscope of the embodiments as defined by the appended claims. Moreover,the scope of the present application is not intended to be limited tothe particular embodiments of the process, machine, manufacture,composition of matter, means, methods, and steps described in thespecification. As one of ordinary skill in the art will readilyappreciate from the disclosure, processes, machines, manufacture,compositions of matter, means, methods, or steps, presently existing orlater to be developed, that perform substantially the same function orachieve substantially the same result as the corresponding embodimentsdescribed herein may be utilized according to the disclosure.Accordingly, the appended claims are intended to include within theirscope such processes, machines, manufacture, compositions of matter,means, methods, or steps. In addition, each claim constitutes a separateembodiment, and the combination of various claims and embodiments arewithin the scope of the disclosure.

What is claimed is:
 1. A method for transferring a container configuredto hold at least one article used in semiconductor fabrication,comprising: moving a transferring mechanism to a first position that isadjacent to the original space; producing an image of an edge of thecontainer that is adjacent to the original space using an opticalreceiver before the container is moved to a destination space; andperforming an image analysis of the image to determine whether to movethe container to the destination space.
 2. The method as claimed inclaim 1, wherein the step of performing an image analysis of the imagecomprises: constructing a movable reference line that is overlapped orparallel to the edge of the container; and comparing the movablereference line with a horizontal reference line extend in a horizontaldirection.
 3. The method as claimed in claim 2, wherein the horizontalreference line indicates a correct position of the edge of the containerwhen the container is centered relative to the original space.
 4. Themethod as claimed in claim 2, wherein the step of comparing the movablereference line with a horizontal reference line comprises: determiningif the movable reference line is parallel to or overlaps the horizontalreference line.
 5. The method as claimed in claim 4, wherein the step ofperforming an image analysis of the image further comprises: determiningthe result of the image analysis is not acceptable when the movablereference line is not parallel to or not overlaps the horizontalreference line; and issuing an alarm signal when the result of the imageanalysis is not acceptable.
 6. The method as claimed in claim 4, whereinthe step of performing an image analysis of the image further comprises:determining the result of the image analysis is acceptable when themovable reference line is parallel to or overlaps the horizontalreference line; and moving the container to a second position that isadjacent to the destination space by the transferring mechanism when theresult of the image analysis is acceptable.
 7. The method as claimed inclaim 6, wherein the destination space comprises a shelf of a stockerfor storing the container.
 8. The method as claimed in claim 1, whereinthe original space comprises a load port of a stocker.
 9. A method fortransferring a container configured to hold at least one article used insemiconductor fabrication, comprising: producing an first image of anedge of the container at a first position that is adjacent to anoriginal space using an optical receiver; moving the container from thefirst position to a second position that is adjacent to a destinationspace using a transferring mechanism when the result of an imageanalysis of the first image is accepted; producing an second image ofthe destination space using the optical receiver; and performing animage analysis of the second image to determine whether to place thecontainer at the destination space.
 10. The method as claimed in claim9, wherein performing the image analysis of the second image comprises:recognizing at least two reference points of the destination space;constructing a stationary reference line that connects the referencepoints; and determining if the stationary reference line is parallel toor overlaps a horizontal reference line extend in a horizontaldirection.
 11. The method as claimed in claim 10, wherein performing theimage analysis of the second image further comprises: determining theresult of the image analysis of the second image is not acceptable whenthe stationary reference line is not parallel to or not overlaps thehorizontal reference line; and issuing an alarm signal when the resultof the image analysis of the second image is not acceptable.
 12. Themethod as claimed in claim 10, wherein performing the image analysis ofthe second image further comprises: determining the result of the imageanalysis of the second image is acceptable when the stationary referenceline is parallel to or overlaps the horizontal reference line; andissuing a signal to the transferring mechanism to drive the transferringmechanism to place the container at the destination space when theresult of the image analysis of the second image is acceptable.
 13. Themethod as claimed in claim 9, wherein the original space comprises aload port of a stocker, and the destination space comprises a shelf ofthe stocker for storing the container.
 14. The method as claimed inclaim 9, wherein performing the image analysis of the second imagecomprises: comparing the second image with a template image by employinga predetermined algorithm.
 15. A stocker for storing containers,comprising: a transferring mechanism, configured to move at least onecontainer from a first position that is adjacent to an original space toa second position that is adjacent to a destination space, wherein thecontainer is configured to hold at least one article used insemiconductor fabrication and the transferring mechanism comprises: arobotic arm; and a blade, positioned on the robotic arm, and configuredto place the container at the destination space; an optical receiver,positioned at the transferring mechanism, and configured to produce anfirst image of an edge of the container at the first position, an secondimage of the destination space, and an third image of the edge of thecontainer that is placed at the destination space; an image processor,connected to the optical receiver, and configured to perform an imageanalysis of the first image, the second image and the third image todetermine if abnormality occurs.
 16. The stocker as claimed in claim 15,further comprising a supporting assembly, positioned on the robotic arm,wherein the optical receiver is positioned at the supporting assembly.17. The stocker as claimed in claim 15, wherein the image processor isconfigured to: constructing a stationary reference line that connects atleast two reference points of the destination space and a movablereference line that is overlapped or parallel to the edge of thecontainer; determining if the stationary reference line is parallel tothe movable reference line; and calculating an angle of the stationaryreference line and/or the movable reference line relative to ahorizontal reference line.
 18. The stocker as claimed in claim 17,further comprising an FDC module, configured to detect faults within thestocker, wherein the FDC module issues an alarm signal when the angle isnot smaller than a preset value.
 19. The stocker as claimed in claim 17,further comprising an FDC module, configured to detect faults within thestocker, wherein the FDC module determines that the result of the imageanalysis is acceptable when the movable reference line is parallel tothe stationary reference line.
 20. The stocker as claimed in claim 19,wherein the FDC module issues a signal to drive the transferringmechanism to the other position for transferring other containers.